Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To investigate the antianginal action of nitroglycerin and nifedipine, systemic and right heart pressures, cardiac output, oxygen consumption, and radionuclide left ventricular ejection fraction and volume were measured in 14 men with stable effort angina and a positive exercise electrocardiogram. Exercise tests were performed on a semiupright bicycle ergometer on no therapy and after intravenous nitroglycerin and sublingual nifedipine, which lowered mean arterial pressure by 20 mm Hg. Exercise tolerance improved from 50 +/- 4 to 61 +/- 5 W on nifedipine and to 79 +/- 4 W on nitroglycerin (p less than 0.01, nitroglycerin vs. nifedipine). At submaximal workloads, both drugs decreased arterial pressure and ventricular volumes, but heart rate was higher on nifedipine. At peak exercise on nitroglycerin (79 W), oxygen consumption, cardiac index, heart rate, and rate-pressure product were significantly increased over peak control and nifedipine values, while systolic pressure and end-diastolic volume were unchanged. Nitroglycerin reduced pulmonary wedge pressure more and systemic diastolic pressure less than nifedipine, so the coronary perfusion gradient was reduced by nifedipine and maintained by nitroglycerin. Also, there was less angina and ST-segment depression after nitroglycerin compared to control or nifedipine, and the left ventricular diastolic pressure-volume relationship was improved only by nitroglycerin. This suggests that the action of nitroglycerin in reducing ischemia is not only due to reduced myocardial oxygen demand, but that myocardial oxygen delivery may also be increased.
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PMID:Comparison of the effects of nifedipine and nitroglycerin on hemodynamic determinants of myocardial oxygen consumption and supply during exertional angina. 247 80

Recent information has suggested that early diastolic filling may be influenced by the left ventricular filling pressure, especially in the failing left ventricle. Acute severe left ventricular dysfunction was induced in 14 dogs by severe left ventricular global ischemia produced by left main coronary artery microsphere embolization until the left ventricular end-diastolic pressure was greater than or equal to 20 mm Hg. To assess the importance of left ventricular filling pressure on left ventricular diastolic filling, nitroglycerin was infused and titrated to reduce left ventricular end-diastolic pressure to less than 15 mm Hg in seven dogs, whereas the remaining seven dogs were observed for 1 h after acute severe left ventricular dysfunction. In both groups of dogs, severe left ventricular dysfunction resulted in left ventricular dilation and elevation of end-diastolic pressure, reduction in area ejection fraction (echocardiographically determined) and an early redistribution of diastolic filling (increased filling fractions at one-third and one-half diastole) despite prolongation of the time constant of left ventricular pressure decline. Pressure-area plots shifted upward and rightward with severe left ventricular dysfunction and were unchanged at 1 h as were all other variables. Nitroglycerin infusion reduced left ventricular size and filling pressure, redistributed diastolic filling to later in diastole as characterized by reduced filling fraction at one-third diastole (left ventricular dysfunction 48.8 +/- 9.7%, nitroglycerin 17.9 +/- 7.9%, p less than 0.001) and shifted downward left ventricular pressure-area plots. Nitroglycerin also improved the time constant of relaxation (left ventricular dysfunction 83 +/- 15 ms, nitroglycerin 52 +/- 15 ms, p less than 0.001) and lengthened the diastolic filling period.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of nitroglycerin-induced reduction of left ventricular filling pressure on diastolic filling in acute dilated heart failure. 250 Apr 71

To determine the effects of intravenous nitroglycerin on the velocities and excursions of the acutely ischemic myocardium, 20 open-chest dogs were studied by use of ultrasound. In 10 dogs with acute septal ischemia, the posterior wall excursion during contraction (B-C excursion), the mean systolic posterior wall velocity, and the posterior wall excursion remained unaltered. Nitroglycerin, however, increased all these parameters (P less than 0.01). In 10 dogs with acute posterior wall ischemia the B-C excursion (aneurysmal bulging) increased (P less than 0.01), but the mean systolic posterior wall velocity and posterior wall excursion decreased (P less than 0.01). Nitroglycerin increased even more the aneurysmal bulging (P less than 0.01) and the other parameters (P less than 0.01). Increased regional blood flow, reduced afterload, and mechanical pulling of the ischemic myocardium seem to be a possible mechanism. The measurements were obtained using the recently described method of the specific points.
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PMID:Left ventricular excursions and velocities during coronary arterial ligation. Effects of nitroglycerin infusion in an experimental model. 250 12

This study was performed to compare the incidence of prebypass myocardial ischemia in patients receiving fentanyl and enflurane for anesthesia along with either pancuronium or vecuronium. Ninety-eight patients with normal left ventricular function were randomly allocated to receive either pancuronium 0.15 mg.kg-1 or vecuronium 0.15 mg.kg-1 in a double-blind manner after fentanyl 40 micrograms.kg-1 for induction of anesthesia for elective coronary artery bypass grafting (CABG). Premedication included diazepam 0.15 mg.kg-1 po, morphine 0.10 mg.kg-1, and scopolamine 0.005 mg.kg-1 im. Two lead Holter monitor recordings (leads V6 and V9) from the time of arrival in the operating suite to institution of cardiopulmonary bypass were analyzed for ischemia by a cardiologist blinded to the choice of muscle relaxant. Intraoperatively, heart rates greater than 90 beats.min-1 and systolic blood pressure +/- 20% of ward values were treated with propranolol, enflurane, or phenylephrine. Nitroglycerin was infused for ECG signs of ischemia or pulmonary hypertension. After induction of anesthesia the heart rate and cardiac index were consistently decreased in patients receiving vecuronium and also lower in these patients compared with those receiving pancuronium. Thirty-two per cent of patients receiving pancuronium received propranolol for heart rates greater than 90 beats.min-1 versus 7% of those who received vecuronium (P approximately 0.01). Eight patients developed 13 episodes of ischemia after administration of the muscle relaxant: four who received pancuronium (n = 44; 9%) and four receiving vecuronium (n = 54; 7%). Four episodes occurred at induction or tracheal intubation, two in each group. There were four perioperative myocardial infarctions as determined by ECG and CPK-MB levels, two in each group.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The incidence of myocardial ischemia during anesthesia for coronary artery bypass surgery in patients receiving pancuronium or vecuronium. 256 17

Twenty patients on chronic beta-blockade for angina pectoris were included in a double-blind randomized cross-over placebo-controlled study on a 2% nitroglycerin gel administered transdermally by an adhesive. Topinitro. The dose, 2.5-10 mg/day, was individually titrated and each treatment period was 28 days. The effect was evaluated by exercise tests and diary cards for anginal attacks and nitroglycerin tablets consumed. Results. In the 17 patients who completed the trial, active treatment did not influence systolic and diastolic blood pressure or resting and maximal heart rate. Maximal performance increased insignificantly from 92 +/- 23 to 96 +/- 20 W. The level at which 1 mm of ST depression appeared increased from 62 +/- 26 to 73 +/- 28 W (p less than 0.05). The number of attacks decreased significantly, from 92 +/- 30 to 14 +/- 28/4 weeks. The reduction in the number of sublingual nitroglycerin tablets consumed was insignificant. Conclusion. Nitroglycerin adhesive, in individual dosages, may improve signs and symptoms of ischemia.
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PMID:Effects on angina pectoris and exercise tests of a 2% nitroglycerin gel adhesive in patients on chronic beta-blockade. A placebo-controlled study. 287 Jun 10

This paper describes a method by which antianginal drugs can be evaluated in the dog heart in situ. Myocardial pH was measured continuously by a micro glass pH electrode inserted in the left ventricular endocardial layers of the dog anesthetized with pentobarbital. Occlusion of the left anterior descending coronary artery (LAD) decreased myocardial pH, and release of the LAD restored the pH. The myocardial acidosis induced by ischemia was metabolic in nature and accompanied by a decrease in the levels of adenosine triphosphate and creatine phosphate and an increase in the levels of lactate in the myocardium. Drugs were injected intravenously 30 min after incomplete (partial) occlusion ot the LAD, lasting until 60 min after drug injection. Propranolol, atenolol, and sotalol markedly attenuated the myocardial pH that had been decreased by LAD occlusion. Nitroglycerin, diltiazem, and nicorandil also attenuated the pH, but these drugs were less active in attenuating myocardial acidosis. Dipyridamole, nifedipine, and beta-2 adrenoceptor antagonists were least active in this regard. It is concluded that myocardial pH can be used as an indicator of myocardial regional ischemia and utilized for evaluation of antianginal drugs.
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PMID:A method for evaluating antianginal drugs in experimental animals: assessment of myocardial ischemia by myocardial pH. 287 74

From January, 1982, through November, 1985, 127 consecutive patients had emergency isolated myocardial revascularization during hypothermic fibrillatory arrest. Mean age was 62.3 years; 27 patients (21.2%) were older than 70 years. Mean ejection fraction was 0.49, with 20 (15.7%) less than 0.35. Intraaortic balloons were present in 109 patients (85.8%). Nitroglycerin was given intravenously to 97 patients (76.3%), and thrombolytic therapy had been used in 12 patients (9.4%). Indications for operation were postinfarction ischemia in 61 patients (48.0%), preinfarction unstable angina in 44 (34.6%), acute ischemia following failed percutaneous angioplasty in 14 (11.0%), and cardiogenic shock in 8 (6.3%). Operation was performed within 1 week of an acute infarction in 47 patients. Mean number of grafts per patient was 4.1. There was 1 hospital death (0.8%) and 1 perioperative myocardial infarction (0.8%). Actuarial survival at 45 months was 90.8 +/- 2.9%. Mean New York Heart Association Classification for the 117 long-term survivors was 1.12.
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PMID:Early and late results following emergency isolated myocardial revascularization during hypothermic fibrillatory arrest. 294 16

Nitroglycerin (NTG) and nifedipine (NIF) have the potential to augment coronary blood flow in addition to reducing peripheral determinants of myocardial oxygen demand as a synergistic protective mechanism during ischemia. To examine these effects, systemic and coronary hemodynamic responses were measured continuously before and during brief periods of myocardial ischemia induced by left anterior descending coronary balloon occlusion in 26 patients undergoing angioplasty (PTCA). Data were compared for two matched occlusion periods, one control and one "drug" occlusion. In 17 patients (NTG group), 200 micrograms of intracoronary NTG was given immediately before coronary occlusion. In nine patients (NIF group), 10 mg of sublingual NIF was given 15 minutes before the "drug" occlusion. NTG significantly but transiently reduced mean arterial pressure (91 +/- 11 to 82 +/- 15 mm Hg, p less than 0.05) and augmented basal coronary blood flow (95 +/- 38 to 127 +/- 54 ml/min, p less than 0.05) but did not alter great vein blood flow (59 +/- 29 vs 61 +/- 29 ml/min) or coronary occlusion pressure (25 +/- 7 to 24 +/- 7 mm Hg) during ischemia. NIF significantly reduced systolic, diastolic, and mean arterial pressure (119 +/- 21 to 95 +/- 8 mm Hg, p less than 0.001) and heart rate-pressure product from control. NIF maintained basal great vein blood flow (125 +/- 41 to 106 +/- 57 ml/min) during reduced myocardial oxygen demand, but did not affect great vein blood flow (73 +/- 29 to 79 +/- 37 ml/min) or coronary occlusion pressures during ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of nitroglycerin and nifedipine on coronary and systemic hemodynamics during transient coronary artery occlusion. 296 25

The efficacy of PY 108-068 (75 and 150 mg/day), a new dihydropyridine calcium antagonist, was compared with placebo for treatment of chronic stable angina. Twelve patients were studied in a placebo-controlled, double-blind, randomized, crossover trial of 2 weeks each. Antianginal efficacy was assessed by the number of episodes of angina and nitroglycerin tablets consumed during each 2-week period, as well as the number of episodes of ischemia during 48-hour ambulatory monitoring and the area and severity of ST-segment depression during 16-point precordial exercise mapping. Nitroglycerin consumption (mean +/- standard error of the mean) decreased from 6.1 +/- 2.9 with placebo to 1.8 +/- 1.5 with 75 mg/day of PY 108-068 (p less than or equal to 0.03) and to 3.6 +/- 2.3 with 150 mg/day of PY 108-068 (p less than or equal to 0.01 vs placebo, difference not significant vs 75 mg/day of PY 108-068), whereas episodes of angina were reduced significantly only by the high dose (p less than or equal to 0.03) (11.1 +/- 3.9 with placebo, 6.3 +/- 2.4 with 75 mg/day of PY 108-068 and 8.1 +/- 3.4 with 150 mg/day of PY 108-068). The low dose alone significantly reduced ST-segment depression during exercise testing (p less than or equal to 0.03) (29.6 +/- 3.6 with placebo, 23.1 +/- 5.6 with 75 mg/day of PY 108-068 and 24.4 +/- 5.0 with 150 mg/day of PY 108-068), whereas neither dose significantly altered the number of episodes of ischemia during ambulatory monitoring.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Usefulness of PY 108-068, a new calcium channel blocker, for angina pectoris. 307 40

The ability to continuously monitor the delicate balance between blood flow and oxygen consumption would be a great asset in the study of myocardial ischemia. The present study was performed, in anesthetized dogs, to validate the use of encased polargraphic oxygen electrodes in the study of myocardial ischemia. Polargraphic oxygen electrodes were placed in the area to be rendered ischemic at fixed tissue depths of 3 mm (epicardium) and 9 mm (endocardium). Endocardial and epicardial oxygen tensions as well as the ratio of endocardial to epicardial oxygen tension and left circumflex coronary flow were monitored. Ischemia was induced by decreasing left circumflex coronary flow by 50%. Upon completion of a 20-min poststenotic period, endocardial pO2, endocardial/epicardial ratio, and coronary flow were significantly decreased (59 +/- 7, 52 +/- 7, and 55 +/- 4%, respectively) whereas epicardial pO2 was slightly decreased. Nitroglycerin (10 micrograms/kg, i.v.) markedly increased endocardial pO2 and endocardial/epicardial ratio above poststenotic control (13 +/- 5 mmHg and 64 +/- 10%, respectively) whereas epicardial pO2 was not significantly decreased. The increases in endocardial pO2 occurred at a point where coronary flow and mean arterial pressure were not significantly changed. Conversely, dipyridamole (125 micrograms/kg, i.v.) significantly increased coronary flow (26 +/- 2 ml/min/100 g) although it did not appreciably alter endocardial or epicardial pO2. It is concluded that encased polargraphic oxygen electrodes provide a quantitative method for determination of oxygen tension in the ischemic myocardium.
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PMID:Measurement of oxygen tension in the ischemic myocardium using encased polargraphic oxygen electrodes. 308 25


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